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Ceiba Pentandra

By persada, on June 30th, 2010

Ceiba pentandra (L.) Gaertn.

Ceiba Pentandra

Protologue
Fruct. sem. pl. 2: 244 (1791)Family
Bombacaceae (APG: Malvaceae)Chromosome number
2n = 72–88SynonymsEriodendron anfractuosum DC. (1824).Vernacular namesKapok tree, silk-cotton tree (En). Fromager, arbre à kapok, ouatier (Fr). Mafumeira, poilão, mufuma, árvore da sumaúma, kapoc (Po). Msufi (Sw).Origin and geographic distributionCeiba pentandra originated in the American tropics. Its natural distribution has been obscured by its widespread introduction after about 1500. Although it has been described as introduced by humans in tropical Africa, there is no historical evidence of such introduction, and there is strong ecological, botanical and cytological evidence that the tree is native to western and central Africa. The dispersal mechanism by which the tree may have crossed the Atlantic Ocean is uncertain, but the fruits float and might have been transported by ocean currents. It has been argued that the tree was domesticated in West Africa, from where it spread to East Africa and Asia. It is now cultivated all over the tropics, but mainly in South-East Asia, especially in Indonesia and Thailand. In tropical Africa the tree appears to be native from Cape Verde eastwards to Chad and southwards to Angola. In addition, there are records of the species in 13 other countries in East and southern Africa (including South Africa) and the Indian Ocean islands, but the tree has probably been planted in all other tropical African countries as well.UsesCeiba pentandra has two main uses, being an important source of fibre and of timber. Historically it has been most important as a source of kapok fibre, the floss derived from the inner fruit wall. Kapok fibre is used for stuffing cushions, pillows and mattresses, and for insulation, absorbent material and tinder. The use of kapok fibre declined in the late 20th century after the introduction of synthetic substitutes. However, there is a renewed interest in the potential of kapok, using new processing techniques, especially in textile applications. The fibre may also have potential as a biodegradable alternative to synthetic oil-sorbent materials, due to its hydrophobic-oleophilic properties.
Currently, the main use of Ceiba pentandra is as a source of timber. The wood (trade names: ‘fuma’, ‘ceiba’) is mostly used in plywood manufacturing, but also for making boxes and crates, and for lightweight joinery. Traditionally, entire trunks are hollowed out as dugout canoes, and the wood is used for lightweight furniture, utensils, containers, musical instruments, mortars, carvings and similar items. It is suitable for insulation, wooden sandals, heels, rafts, floats, lifeboats, models, insulation and particle board. The buttresses are made into doors, table tops, plates and trays.
The wood is suitable for papermaking. Although it has been recorded to be used as fuelwood in DR Congo, it is not considered very suitable as such, because it only smoulders. The wood can be used for fumigating huts or clothes. Wood ash is used as kitchen salt and for soap making. The bark is used for making hut walls and doors and yields a gum and a reddish brown dye. The leaves and shoots are fodder for goats, sheep and cattle. The leaves, flowers and young fruits are eaten cooked into sauces. The flowers are visited by bees, producing an amber-coloured honey with a characteristic taste. Ash from the fruits is locally made into snuff.
A use that has attracted commercial interest is as a source of seed oil, which has been used in soap, and pharmaceutical manufacturing. The oil can also be used for illumination, paint manufacturing and lubrication. It has been used for culinary purposes, but this is not advisable for health reasons. The seed cake is good as feed or as fertilizer. The seeds are eaten roasted or they are pounded and ground into meal or cooked in soup. They are, however, said to upset the digestion.Ceiba pentandra finds wide application in African traditional medicine. The root forms part of preparations to treat leprosy. Pulverized roots and root decoctions are taken against diarrhoea and dysentery. Root decoctions are oxytocic. Macerations of the root bark are drunk against dysmenorrhoea and hypertension. The root and stem barks are credited with emetic and antispasmodic properties. Stem bark decoctions are used in mouth washes for treating toothache and mouth problems, and are taken to treat stomach problems, diarrhoea, hernia, gonorrhoea, heart trouble, oedema, fever, asthma and rickets; they are also applied on swollen fingers, wounds, sores, furuncles and leprous macules. Bark extracts are considered emetic; they are drunk or applied as an enema. Macerations of the bark are a cure for heart trouble and hypertension, and are credited with stimulant and anthelminthic properties. The powdered bark is applied on wounds. Gum from the bark is an astringent and is used to treat diarrhoea and as an abortifacient. The leaves are credited with emollient and sedative properties. They are used against scabies, diarrhoea, fatigue and lumbago, and as an alterative, laxative and abortifacient. Young leaves are warmed and mixed with palm oil to be eaten against heart problems. Pounded leaves are applied as a dressing on sores, tumours, abscesses and whitlows. Leaf sap is applied on skin infections, and drunk to treat mental illness. Leaf macerations are drunk or used in baths against general fatigue, stiffness of the limbs, headache and bleeding of pregnant women. Leaf preparations are used as an eye-bath to remove foreign bodies from the eye. A decoction of the leaves is applied to treat conjunctivitis and wounds in the eye, and is used for bathing and massage to treat fever. In veterinary medicine a decoction of the leaves is given to treat trypanosomiasis. The flowers are taken to treat constipation, and flowers and fruits are credited with emollient properties. The powdered fruit is taken with water against intestinal parasites and stomach-ache. Kapok fibre is used for cleaning wounds. The seed oil is rubbed in for treatment of rheumatism and applied to heal wounds.Ceiba pentandra is planted as a wayside and shade tree. The tree is sometimes left by farmers after clearing the forest for agricultural land, to serve as a shade tree for cultivation of crops such as coffee and tea. It is increasingly planted as an ornamental in subtropical areas. The kapok tree has sacred significance for local peoples in many parts of the world, including tropical Africa, where it often serves as a tree under which meetings are held.Production and international tradeKapok fibre was an important commercial fibre before the Second World War, with Indonesia being the most important producer. After the Second World War, Indonesian production decreased and Thailand became the main producer, but later Indonesian kapok production increased again from less than 30,000 t per year in the 1960s to about 80,000 t per year in 2000–2004, whereas the annual kapok production in Thailand remained stable at 40,000–45,000 t, according to FAO statistics. Most of the kapok produced is not exported.
In tropical Africa production and trade of Ceiba pentandra historically has centred on the kapok fibre. In the early 20th century, colonial foresters planted the tree widely in West Africa, as well as in East and southern Africa. Plantings were generally made along roads, providing the benefit of shade in addition to fibre production, and only a few orchards were planted for fibre production, e.g. in Côte d’Ivoire, Burkina Faso and Ghana. During the mid-1900s, kapok was a valuable export product for many West African countries, but its importance declined from the 1960s onwards. Currently, production and trade centres on the timber, mainly for plywood production. Plywood manufacturing in Africa expanded from the 1960s as several countries pursued import substitution, and as world demand for plywood increased rapidly. Commercial use of Ceiba pentandra timber has risen with the decline of more valuable species. Exploitation relies almost entirely on naturally occurring trees, although recently efforts have been made to establish plantations in Ghana. In both Ghana and Nigeria Ceiba pentandra is considered a ‘lesser-known’ or ‘lesser-used’ species, and its future use is expected to increase. The wood has a relatively low value in international markets, but it is an important export product for several African countries. According to recent ITTO statistics Ghana exported 61,000 m³ Ceiba pentandra plywood in 2003, at an average price of US$ 293/m³, 54,000 m³ in 2004, at an average price of US$ 292/m³, and 37,000 m³ in 2005, at an average price of US$ 301/m³. Ghana exported comparable volumes of Ceiba pentandra veneer during these years: 62,000 m³ at an average price of US$ 242/m³ in 2003, 52,000 m³ at an average price of US$ 271/m³ in 2004, and 48,000 m³ at an average price of US$ 274/m³ in 2005. In 2005 the average price of Ceiba pentandra logs in international markets was US$ 156/m³, while the export price of sawn wood from Ghana was US$ 246/m³. ‘Ceiba’ was by far the least expensive veneer for plywood exterior and core stock in Ghana in 2005. In 2006 it accounted for 19.6% of Ghana’s timber exports, the largest percentage of any of the 87 species exported that year. Local and national markets for Ceiba pentandra timber are weak; the average log price in Ghana’s domestic market was US$ 31–55/m³ in 2005, while the average sawn wood price was US$ 53/m³.Properties
The wood is creamy white, streaked with yellow, brown, pink, and/or grey, but discoloration due to fungal attack is extremely common; the heartwood is not clearly demarcated from the sapwood. The grain is interlocked, sometimes irregular, the texture coarse. Growth rings are prominent. The silica content is low.
The wood is lightweight, with a density of (200–)240–380(–450) kg/m³ at 12% moisture content. The density of the wood increases strongly from pith to bark, and varies between trees from different sites. The wood seasons rapidly, with only slight risks of cupping, springing, twisting or bending. The rates of shrinkage from green to oven dry are 2.5–3.5% radial and 3.9–6.7(–9.1)% tangential. The dried wood is stable in service, making it ideal for plywood core stock.
The wood is particularly weak and soft. At 12% moisture content, the modulus of rupture is 26–61 N/mm², modulus of elasticity 2300–5600 N/mm², compression parallel to grain 14–26 N/mm², shear 2–4 N/mm², cleavage 4–13 N/mm, Janka side hardness 1060–1110 N, Janka end hardness 1820–1960 N and Chalais-Meudon side hardness 0.4–1.0. The wood is brittle when dry.
The wood is difficult to saw cleanly and finish smoothly. Sawn surfaces tend to be woolly, and sharp cutters are necessary to achieve a smooth, finished surface. The blunting effect on cutting edges is low. Shaping, boring, turning and mortising often tear the grain, but planing and sanding produce fine results. The wood holds nails and screws poorly, and must be glued for fastening. Fresh logs, if free of insects and fungal decay, are easy to peel into sheets for plywood manufacturing. The wood can be glued satisfactorily and takes paint very well. It has been recorded to cause itching in workers handling it.
The wood has very low durability, being liable to attacks by insects and fungi. It is amongst the most vulnerable African timbers to termites, Lyctus beetles, and other boring insects. It is susceptible to white-rot and blue-stain fungi, but resistant to very resistant against brown rot. The wood is extremely vulnerable to decay when in contact with the soil. It readily absorbs preservatives: both vacuum-pressure and open tank systems give good penetration and absorption.
The wood contains cellulose 39%, pentosans 18%, lignin 24% and ash 4%. The solubility in alcohol-benzene is 2.7%, in hot water 8.8%. The wood fibre cells are 2 mm long and 30–35 ?m wide. Pulp yields are low.
The total dry matter of ripe fruits, by weight, is composed of 48% shell, 21% fibre, 25% seed and 6% placenta. Kapok fibre cells are (8–)19–22(–35) mm long and (10–)19–20(–30) ?m wide, smooth, transparent, cylindrical, with a wide lumen and thin walls. Kapok fibre contains about 43% ?-cellulose, 32% hemicellulose, 13–15% lignin and 1% ash. It is resilient, elastic, light (8 times lighter than cotton), water-repellent and buoyant (5 times more than cork). In an uncompressed state, it can support 20–30 times its own weight in water, because when the fibre is immersed in water, the lumen only partly fills with water and contains many air bubbles. Kapok fibre has a low thermal conductivity and very good sound-absorbing properties. A disadvantage is its high inflammability, but techniques have been developed to make it non-flammable. In its natural form, kapok fibre cannot be spun, because of the smoothness of the outer surface. However, techniques have been developed to make spinning possible. The fibre is long-lasting and is not attacked by fungi or pests. White-coloured fibre is preferred. Kapok fibre is irritating to the eyes, nose and throat, and workers exposed to kapok dust for long periods may develop chronic bronchitis. People involved in processing of kapok fibre are advised to wear protective masks. Because of the irritant fibres and the spreading root system, the tree is less suitable as shade or wayside tree.
The seeds yield 11–28% oil, with as main fatty acids: palmitic acid (10–16%), stearic acid (2–9%), oleic acid (49–53%) and linoleic acid (26–29%). The oil resembles cotton-seed oil, but does not contain gossypol. It does contain cyclopropenoid fatty acids such as malvalic acid (7–8%) and sterculic acid (3–4%), which cause abnormal physiological reactions in animals. Therefore the consumption of kapok seeds or seed oil should be discouraged, unless the cyclopropenoid acids have been chemically removed. Per 100 g the presscake contains approximately: moisture 14 g, protein 26 g, fat 8 g, carbohydrates 23 g, fibre 23 g and ash 6 g. The K content of the shell is about 3%, and that of the ash 20–23%.
The composition of leaves from Côte d’Ivoire per 100 g dry matter was: energy 486–631 kJ (116–151 kcal), protein 19.1–26.5 g, fat 2.2–2.7 g, carbohydrate 8.0–8.6 g, fibre 55.1–62.8 g, Ca 649–1200 mg, Mg 440–452 mg, Fe 7.0–8.3 mg, carotene 22.7–25.5 mg, riboflavin 0.60–0.73 mg and ascorbic acid 148–250 mg.
A root bark extract has shown in-vivo hypoglycaemic activity in rats. Bark extracts have shown in-vivo and in-vitro anti-inflammatory activity, in-vitro anthelmintic activity, and curare-like activity on anaesthetized cat nerves. Bark decoctions and sesquiterpene lactones isolated from the root bark have shown antimicrobial activity. Leaf extracts have shown in-vitro activity against sickle cell anaemia.Adulterations and substitutesCeiba pentandra wood is sometimes sold in mixed consignments with that of Bombax buonopozense P.Beauv., but the wood of the latter is darker and heavier. Ceiba wood is heavier than balsa (Ochroma pyramidale (Cav. ex Lam.) Urb.), but lighter and weaker than obeche (Triplochiton scleroxylon K.Schum.). It is not as lustrous as balsa or obeche.Kapok fibre is obtained from several other African trees, especially Bombax buonopozense P.Beauv. and Bombax costatum Pellegr. & Vuillet. Fibre obtained from the red silk-cotton tree (Bombax ceiba L., synonym: Bombax malabaricum DC.) has many of the qualities of that of Ceiba pentandra, but is less resilient, has a more brown or yellow colour, and can support only 10–15 times its own weight in water. For industrial purposes kapok fibre has largely been replaced by synthetic products, for instance for the production of life-jackets.Description
Very large, deciduous tree up to 60 m tall, with roots spreading quite horizontally, 10 m or longer, in the upper 40–80 cm of the soil; bole branchless for up to 35 m, straight, usually cylindrical, up to 200(–240) cm in diameter, usually with large plank-like buttresses up to 3(–8) m high extending 1–2 m from the bole; bark surface smooth, pale grey, usually with scattered conical spines 1–1.5 cm long, inner bark pale to pinkish red with vertical stripes of white or yellowish tissue; crown of emergent trees in the forest spreading and umbrella-shaped with no lateral branches lower along the bole, crown of trees in more open vegetation ovoid with lateral branches along much of the bole; branches whorled, dimorphic, branches usually in whorls of 3, horizontal or ascending, older branches often spiny. Leaves alternate, digitately compound, with 5–9(–15) leaflets; stipules linear to narrowly triangular, up to 1 cm long, caducous, leaving scars; petiole (3.5–)5–27 cm long, thickened at base, apex expanded into an almost circular disk; petiolules up to 3 cm long; leaflets sessile, obovate to elliptical, (3.5–)5–21 cm × (1–)2–6.5 cm, cuneate at base, acuminate at apex, entire or sometimes slightly toothed at margin, glabrous, pinnately veined with lateral veins in 7–18(–20) pairs. Inflorescence an axillary fascicle, often on leafless branches, 1–15-flowered. Flowers bisexual, 5-merous, regular, strongly but unpleasantly scented; pedicel 2–5(–8) cm long; calyx campanulate, 9–15 mm × 11–14 mm, lobes rounded to nearly acute, glabrous outside, hairy inside; petals united at base, oblong-spatulate, 22–46 mm × 6–13 mm, pink, creamy yellow or white, hairy outside, glabrous inside; stamens 5–15, united at base in a staminal column, dividing into 5(–6) branches 2.5–5 cm long; ovary semi-inferior, 3–6 mm in diameter, 5-celled, style 2.5–4 cm long. Fruit a pendulous, oblong-ellipsoid capsule 7.5–30(–60) cm × 3–15 cm, dehiscing with 5 valves (‘shells’) or indehiscent, smooth-valved, brown when ripe, many-seeded. Seeds almost globose, 4–6 mm in diameter, glabrous, dark brown or black, embedded in copious white or greyish floss. Seedling with epigeal germination.Other botanical informationCeiba comprises about 17 species, most of them occurring in tropical America. Ceiba pentandra is variable. Sometimes 3 varieties are distinguished.
var. caribaea (DC.) Bakh., occurring in the forests of the American tropics and in West Africa; very large tree up to 70 m tall, with unforked, buttressed and spiny bole and horizontal branches, leaves narrow, flowering irregular, fruits rather short and broad, dehiscent, fibre grey to white; 2n = 80, 88.
var. guineensis (Schumach. & Thonn.) H.G.Baker, occurring in savanna woodlands of West Africa; small to medium-sized tree up to 18 m tall, bole spineless without buttresses, often forked, branches strongly ascending, leaves broad, flowering annually, fruits elongated and narrow at both ends, dehiscent, fibre grey; 2n = 72.
var. pentandra, the cultivated kapok of West Africa and Asia; medium-sized tree up to 30 m tall, bole unbranched, usually spineless, buttresses small or absent, branches horizontal or ascending, leaves intermediate between the 2 other varieties, flowering annually after leaf-shedding, fruits short or long, narrowed at both ends or banana-shaped, usually indehiscent, fibre usually white; 2n = 72–84. It would be more appropriate to classify this variety as a cultivar group.Anatomy
Wood-anatomical description (IAWA hardwood codes):
Growth rings: (1: growth ring boundaries distinct); (2: growth ring boundaries indistinct or absent). Vessels: 5: wood diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; 23: shape of alternate pits polygonal; 26: intervessel pits medium (7–10 ?m); 27: intervessel pits large (? 10 ?m); 31: vessel-ray pits with much reduced borders to apparently simple: pits rounded or angular; 35: vessel-ray pits restricted to marginal rows; 43: mean tangential diameter of vessel lumina ? 200 ?m; 46: ? 5 vessels per square millimetre; (47: 5–20 vessels per square millimetre). Tracheids and fibres: 61: fibres with simple to minutely bordered pits; 66: non-septate fibres present; (68: fibres very thin-walled); 69: fibres thin- to thick-walled. Axial parenchyma: 77: axial parenchyma diffuse-in-aggregates; 79: axial parenchyma vasicentric; (86: axial parenchyma in narrow bands or lines up to three cells wide); (89: axial parenchyma in marginal or in seemingly marginal bands); 91: two cells per parenchyma strand; 92: four (3–4) cells per parenchyma strand. Rays: 98: larger rays commonly 4- to 10-seriate; (99: larger rays commonly > 10-seriate); 102: ray height > 1 mm; 106: body ray cells procumbent with one row of upright and/or square marginal cells; 107: body ray cells procumbent with mostly 2–4 rows of upright and/or square marginal cells; 110: sheath cells present; 114: ? 4 rays per mm. Storied structure: 120: axial parenchyma and/or vessel elements storied. Mineral inclusions: 136: prismatic crystals present; 137: prismatic crystals in upright and/or square ray cells; (138: prismatic crystals in procumbent ray cells); 141: prismatic crystals in non-chambered axial parenchyma cells.
(P. Mugabi, A.A. Oteng-Amoako & P. Baas)Growth and development
Without any pre-treatment seeds germinate slowly (less than 10% one month after sowing) and germination may continue for 3–4 months. Bush fire may cause simultaneous germination of seeds. Growth is relatively fast. Seedlings planted in Ghana were 29 cm tall 6 weeks after germination, and 63 cm after 51 weeks. The annual increases in height and diameter during the first 10 years are about 1.2 m and 3–4 cm, respectively. In forest gaps height growth may be 2 m/year. The tree is obligately deciduous, losing its leaves for 10–14 weeks in the dry season, and it usually flowers annually in the leafless period. Leafing and flowering periods are more regular in drier parts of the distribution area; in moister areas, leafing and flowering periods are highly irregular. The flowers open at night and are senescent by midday; they are pollinated by bats, but are also visited by moths and bees. The fruits ripen 80–100 days after flowering, the dehiscent types releasing kapok with loosely embedded seeds that are wind-dispersed.EcologyCeiba pentandra requires abundant rainfall during the vegetative period and a drier period for flowering and fruiting. It thrives at elevations below 500 m, but it grows up to altitudes as high as 4000 m. Night temperatures below 17°C retard germination of the pollen grains, which limits the area in which the trees can be grown for the fruit fibre to latitudes between about 20°N and 20°S, and altitudes below 1500 m. Rainfall should be about 1500 mm per year. In its area of natural distribution, the average annual rainfall is 750–3000 mm. The dry period should not have more than 4 months, and in this period a well-distributed rainfall of 150–300 mm is required. In drier areas, some of the water demand may be met by groundwater. For best results the tree should be planted on deep, permeable soils without waterlogging. The tree is easily damaged by strong winds, and it does not survive fire.Ceiba pentandra occurs in rainforest, and in gallery forest in drier areas. It is a pioneer in secondary forest and riverine forest, and is rarely found in primary forest. It grows fast in canopy openings caused by disturbance, becoming an emergent in mature stands. In drier parts of its range, the tree is increasingly rare in natural vegetation, but may be abundant in settlements and fields in humid to semi-arid zones. In these settings, it may be planted, or self-sown seedlings may benefit from human protection against livestock and fire. Throughout West Africa, Ceiba pentandra is associated with occupied and abandoned settlements.Propagation and plantingCeiba pentandra is usually propagated by seed, although it can also be grown from cuttings. The 1000-seed weight is 20–100 g. The seeds are easily separated from the fruit floss, in which they are loosely held, by shaking dehiscent fruits in a bag. Seeds may be stored up to one year in glass or plastic containers at 4°C and 60% relative humidity. Long-term seed storage has not proven successful, because the seed oil goes rancid. Fresh seeds have germination rates of 90–100% within 3–5 days after sowing, when pre-treated by scoring lightly and soaking in water for 24 hours or by soaking in boiling water for 5 minutes. Germination is good in sandy soil with temperatures of 20–30°C. When the young plants are 12–15 cm tall, they can be exposed to full sunlight. Ceiba pentandra is light-demanding, and growth is spindly and poor and mortality is high for seedlings and saplings in shaded locations, including small canopy gaps that close relatively quickly. Young plants can be grown in a nursery and be transplanted into the field when they are 4–10 months old. It is recommended, however, to sow directly on land which has been properly cleared for planting. Ceiba pentandra is easily propagated from cuttings, which should be taken from orthotropic branches. Trees raised from seeds root deeper than those raised from cuttings, but develop slower.
Recommended planting distances are 4.5–5 m × 4.5–5 m, with elimination of every second row after 6 years, to arrive at a spacing of 10 m between rows. Seeds may also be sown at about 7 m spacing between trees, with an understorey of crops until the canopy closes, about 5 years after planting. In the first 2 years after planting, vegetation must be cleared periodically around saplings. General tending may be necessary in the following years, by cutting climbers and lianas, and removing dead and diseased trees. Plantations need not be thinned if planted with 7 m spacing unless intercropped with smaller tree crops.ManagementCeiba pentandra requires little attention, but the soil must be occasionally weeded and loosened. Fertilizers are not usually applied and there is no information on fertilizer experiments. Pruning is not required. The tree performs best in locations where the vegetation is actively managed to maintain sunny conditions and to reduce climber burden on the trees. Coppicing, pollarding and lopping is possible.
In forests in Ghana the number of trees with a diameter above 90 cm is about 35 per km². In natural forests in Côte d’Ivoire and Cameroon average standing volumes of 6–8 m³/ha have been measured, in Gabon standing volumes were only 0.2–0.6 m³/ha.Diseases and pests
High seedling and sapling mortality may occur in humid climates as a result of leaf spot, dieback, damping off and anthracnose. These infections are caused by various fungal pathogens. Tests have shown that leaf spot and anthracnose are caused by Colletotrichum capsici, whereas Fusarium solani and Lasiodiplodia theobromae were associated with dieback of stem. The most effective fungicides for preventing these infections are Kocide (Cu-hydroxide, at 6.6 g/l) and Aliette (Aluminum tris(ethyl phosphite), at 5 g/l), although these fungicides retard the growth of seedlings. Ceiba pentandra is a host tree of Cacao Swollen Shoot Virus (CSSV) causing swollen shoot disease in cocoa, a disease which has had a devastating effect on cocoa production in Ghana and neighbouring countries. Ceiba pentandra itself shows considerable resistance.Harvesting
The tree is usually felled above its buttresses, which may necessitate the construction of platforms. To obtain kapok fibre, the fruits are harvested when fully ripe and, in dehiscent types, before they open. Ripeness is indicated by the fruit colour changing from green to brown and the surface possibly becoming wrinkled. The fruits are normally harvested by knocking them off the tree before. Trees normally start to bear fruit when they are 3–8 years old.Yield
A tree 70 cm in diameter above the buttresses yields on average 4 m³ of timber, and trees 100 and 150 cm in diameter above the buttresses 9.3 m³ and 23 m³, respectively.
Under optimum conditions a full-grown plantation tree may yield 330–400 fruits per year, giving 15–18 kg fibre and about 30 kg seed. A satisfactory average annual fibre yield is about 450 kg/ha, whereas about 700 kg/ha is considered very good.Handling after harvest
After the trees have been felled, the wood is liable to attacks by insects and fungi, and logs must be treated with preservatives, extracted, sawn and dried as soon as possible.
To obtain kapok fibre, fruits are hulled as soon as possible after harvesting. Drying is carried out in dry air or with fans in cage-like structures. The seeds lie loose in the floss, and therefore de-seeding is easy. They are usually separated from the floss by beating. The quality of kapok fibre is judged by fibre length, freedom from seeds and foreign matter, moisture content, colour, smell and lustre. Excessive pressure should not be used when kapok is baled for export as it is likely to destroy the elasticity and diminish the quality of the fibre.Genetic resources
In view of its pantropical distribution, Ceiba pentandra does not seem to be threatened with genetic erosion. The tree is traditionally protected in many parts of Africa, and is legally protected in several countries, especially in drier parts of its range. However, commercial timber harvesting of Ceiba pentandra is considered unsustainable in some areas, including Côte d’Ivoire and Ghana. The largest kapok germplasm collection is kept at the Indonesian Tobacco and Fibre Crops Research Institute in Malang (Indonesia) and contains 180 accessions. Some accessions are held at CNSF (Centre National de Semences Forestières) in Ouagadougou (Burkina Faso).Breeding
Some work has been done on the selection and propagation of trees with white floss, indehiscent pods and lacking spines. Microsatellite markers have been developed and characterized, providing a tool for rapidly generating information on patterns of genetic variation, gene flow and mating systems.Prospects
Timber industries in Africa have become increasingly reliant upon Ceiba pentandra in recent decades, and use of the tree will probably intensify in the near future as many African nations have shifted toward less valuable, historically underutilized species. While Ceiba pentandra has clear value in plywood manufacture, increased rates of harvesting should not be accepted uncritically for two main reasons. First, although the use of kapok fibre has declined in recent decades, this resource has high potential as new processing techniques are being developed. Use of the tree as timber should not preclude development of improved fibre industries. Second, in the long term natural regeneration may be insufficient to sustain increased use as a source of timber, while minimal efforts have been undertaken to develop plantations in tropical Africa.Major references
• Baker, H.G., 1965. The evolution of the cultivated kapok tree: a probable West African product. In: Brokensha, D. (Editor). Ecology and economic development in tropical Africa. Research Series No 9. Institute of International Studies, University of California, Berkeley, United States. pp. 185–216.
• Bolza, E. & Keating, W.G., 1972. African timbers: the properties, uses and characteristics of 700 species. Division of Building Research, CSIRO, Melbourne, Australia. 710 pp.
• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.
• Chudnoff, M., 1980. Tropical timbers of the world. USDA Forest Service, Agricultural Handbook No 607, Washington D.C., United States. 826 pp.
• CIRAD Forestry Department, 2003. Fromager. [Internet] Tropix 5.0. http://agritrop.cirad.fr. Accessed April 2007.
• CTFT (Centre Technique Forestier Tropical), 1975. Fromager. Bois et Forêts des Tropiques 163: 37–51.
• Gibbs, P. & Semir, J., 2003. A taxonomic revision of the genus Ceiba Mill. (Bombacaceae). Anales del Jardín Botánico de Madrid 60(2): 259–300.
• Sahid, M. & Zeven, A.C., 2003. Ceiba pentandra (L.) Gaertn. In: Brink, M. & Escobin, R.P. (Editors). Plant Resources of South-East Asia No 17. Fibre plants. Backhuys Publishers, Leiden, Netherlands. pp. 99–103.
• Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan, 248 pp.
• Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.Other references
• Alvarado, C.R., Alvarado, C.A. & Mendoza, O.O., 2002. Ceiba pentandra (L.) Gaertn. In: Vozzo, J.A. (Editor). Tropical tree seed manual. USDA, Forest Service Publication, s.l., Washington DC, United States. pp. 394–396.
• Apetorgbor, M.M., Siaw, D.E.K.A. & Gyimah, A., 2003. Decline of Ceiba pentandra seedlings, a tropical timber species, in nurseries and plantations. Ghana Journal of Forestry 11(2): 51–62.
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C.S. Duvall
Department of Geography, Bandelier West, Room 121, University of New Mexico, Albuquerque, NM, 87131, United States